DOE-BASED INTERFEROMETRY

Diffractive optical elements (DOE) can generate very general wave fiel ds via diffraction. In interferometry DOE's ran be used in different w ays. The DOE can be used as reference in aspheric testing where refere nce normals are difficult to establish. DOE's provide also the possibi lity of beam splitting in a rather straightforward manner. This enable s the test of very general objects in grazing incidence or the test of optical elements via shearing interferometry. DOE's open up the alley to miniaturization and in addition enable achromatized LDA beam split ters making the use of high power semiconductor lasers feasible. Accur acy and plotting problems for DOE's are also addressed.